Method of making metallic bellows



' 1,644,823 fiat, E1, 1927. 1 H. B. FAY

METHOD OF MAKING METALLIC BELLOWS Filed Oct.28, 1924 Horace ESFQy ATTONEYS 1,644,823 UNITED STATES PATENT OFFICE.

HORACE B. FLY, OI SEAKEB-HEIGHTS, OHIO.

Patented Oct. 1 1, 1927.

mnrnon or minim un'rmro minnows.

Application filed October 28, 1924. Serial No. 746,881

'I of making deeply corrugated, flexible,

The present invention relates to a method tubular metal walls ormetallic bellows, and more particularly to an improved method of makingsuch bellows by combined mechanical and fluid pressure operations toproduce a superior bellows and one having substantially uniform wallthickness and temper throughout each portion of the corrugation.

- constituting, however, but

- plications of the principles of my invention.

through "j has the disadvantage o.

by my improved method. I

In said annexed draw1ng: a

1 is a longitudinal central section a tube showing co-operative rolls inposition to forma partial corrugation in the wall of such tube; Fig. 2is a longitudinal section showing one wall ofa tube after formation intocorrugations by means of a collapsible die; and Fig. 3 is a longitudinalsection through aportion of bellows formed Fig.

, Metallic bellows may be manufactured either by rolling corrugationsinto the wall of the tube or by expanding the wall of a tube by fluidpressure exerted within the tube to produce externally extendingcorrugations,

or by a combination of these two methods in which the corrugations arefirst partially formed? in the tube 'wall' by fluid pressure.

"and are then brought to their'final form by mechanical operations, suchas rolling. The

last-named roces's, th at is, the'combination P which inclu es fluidpressureexpansi'on followed by'mechanicale ansion or rolling,

method, which is that tiny'particles of grit cling to the surface,eith'e'rpf-the rolls or of the tube," and are'lrolledtinto the tubewallduringfthe "rollin i make the tube wea operation, tending to p at thatpoint and l able to l)refalm'ge when" any."-extreme-pressure is'applieditoit. 1

esista'njcef of the" bellows is "tested during heir formation} that is,the ressure neces= he tube wa .into corrugat me T e y higher than ny psets given to. the bellows axis of the tube.

1 the usual rolling "f'lhe one"articular advantage of bellows made by auid' pressure process is that the which is ap lied, to the corru ationsin actual service ater, and also in t e fluid pressure method there isno possibility of grit becoming embedded in the wall of the corrugationsand weakening these walls.

The principal object of the present invention is the provisionof amethod which will combine the advantages of both the mechanical andfluid pressure methods, while retaining all of the advantages andcharacteristicsy the fluid pressure method, which are the economy ofmanufacture, the testing of the bellows during its final formation underhigh. pressure, and the uniform stretching of the metal in each'corrugation, which tends to make the corrugations of uniform strengthand resilienc I make my improved bellows by first su jecting arelatively thin tubular wall to the' mechanical action of co-operativerolls disposed on opposite sides of the tube wall, as shown in ig. 1.wall 1 is mounted between a pair of rolls 2 and an opposed roll 3, therolls 2 and 3 being movable toward and away from each other. Inoperation the tube is first positioned over the rolls 2, after whicheither the tube, containing the spaced ,rolls 2, is moved toward theroll 3 or the roll 3 is moved up against the wall of the tube op 0- siteto the space between the rolls 2, an is thus caused to form anencircling groove or corrugation 4 in the tube wall.

A series of corrugations is formed in the In this figure the tube rugations being equall s aced and bein of course parallel: and al right.angles to the The tube, with its inwardmay then be extions to providecomplete exteriorly an interiorly extending corrugations by. theapplication of fluid pressure within the tube, while suply extendingcorrugations anded between these corru porting the previouslyformedcinward cor- ,rugations against expansion, This .operation may beperformed in apparatus of the character described and claimed in thepatent to F. K. Bezzenberger, No. 1,506,966, dated September2, 1924, inwhich a tube'is dis (1 within a partible die, eachhalf of which includesa series which, in the closed pletely encircle and enga a of thetubevIn- Fig. 2 I ave shown a tube wall. provided th inwardly extendmg' cmmons 4 e dle rings 5 tion of the die, comgainst the wall of halfringsor dies and 6 of the ty e shown in the above-named patent. In thiscase, however, the rings 5 and 6 are constructed to enter and engagesnugly against the previously formed inner corrugations. After the tubehas been so disposed within the die rings fluid pressure is exertedwithin the tube and acts to expand the portions of the tube wall lyingbetween the rlngs outwardly, while at the same time an increasinpressure is applied longitudinally of the tube to colla se the same, therin s being collapsed or rought together at t e same time so that theoutwardly extendingscorrugations which are in process of formation areconcluded a ainst the rings 5 and 6, which, at the finish of theoperation, are in the relation shown in Fig. 2 at the upper part of thefigure. In this way the entire corrugation is formed, each corrugationconsisting of the previously formed inner portion 4 and the outwardportion 7, the corrugations having parallel radial ortions 8.

In roducing a bellows. in t is manner it shoul be remembered that theremay be not only a stretching of the metal produced by increasing thelength of that portion of the tube measured longitudinall which is beingcorrugated, but also that this ortion of the tube wall is beingstretched a so b the increase in diameter, that is, there is both alongitudinal and a circumferential stretch given to the metal. It willbe apparent that the circumferential stretch .will be difi'erent whenthe corrugations are thrown inward" and the diameter reduced from thestretch imparted to a corrugation which is thrown outwardly, and I soproportion the initially formed inward corrugation and the subsequentlyformed outward corrugation that the stretch which is thus given to themetal is substantially the same, which will provide a uniform temper inboth the crests of theinner and outer corrugations. The temper in themetal in the radial planes 8 is also substantially the same as thatatthe'crests of the corrugations, since in a bellows made by a singlefluid pressure operation, it has,

been found, the metal will flow and the stretch will be distributedthroughout the en-' tire corrugation very much more evenly than ispossible when a tube wall vis corrugated between rolls which merelystretch the portion of the metal lying between the crests of the spacedrolls.

The distribution of metal from the two o rations is shown in anexagerated way in i 3, in which the'thickest portion of the wal of thecorrugation is at the points 9,

4 which correspond to the points -10in the. tube in the condition shownin Fig. -1. The wall bellows by the resent method to prevent anyincrease, in tie surface length of the bellows measured along a linelying on the surface of a tube or bellows and disposed arallel with theaxis of the same, as it has een found that if the tube is materiallylengthened in this dimension this lengthening is produced by unduestretchin of the metal inthe outer corrugations, whic would impart toogreat hardness and temper to the walls at these points and cause theirearly breaka e. It-will of course be apparent that in the initialmechanical step of the resent method the tube length is. increase.somewhat, and it is therefore desirable to actually shorten the tubelength in the fluid pressure operation by an amount which substantiallyequals the increase in the, first operation.

By the present method bellows having ver deep'corrugations may be made,since -di erent portions of the metal wall are the corrugation, that is,the metal is at no point stretched as much as is the case when thecorrugation is formed entirely outwardly, {gas is the case of bellowsmade by a single uid pressure expansion). In the first step ofmy methodthe metal may be stretched inwardly an amount producing the maximum safeworking temper in this portion,

say 20% to 40%, after which other portions of the tube are stretchedoutwardly until the same maximum temper is there present, but in thissecond operation the previously stretched or tempered metal of the innerportion of the corrugation is not again stretched or subjected to anytempering action. The .obvious advantage of thi; method is the aplication of the fluid pressure method to t e production of deep, evenlytempered corrugations which is a ty of corrugation not otherwisepossible wit use of 'a uid pressure operation, at least withoutsubiequent rolling operations with the risks of introducingimperfections into the metal wall.

The advantages of the present product are the uniformity of the wallthickness and temper throughout the entire area of each corrugation, andthe consequent longer life of the bellows in service, together with thefact'that as the bellows is finished in a fluid ressure operation, whichinvolves the estabishment of a relativel' high pressure with- ".in thebellows,it is t us possible to automatically test each bellows duringits manufacture, and any bellows which will withstand this pressure willof course withstand the same or lower pressures in service. In

. addition to this advantage the completion of the bellows. in a fluidpressure 0 ration avoids an possibilit of mechanic yworking into t ewalls 0 the corrugations rticles of grit whichwould reduce thic essat\these points and tend to shorten the life ito of the bellows and-itsresistance'to leakage at high pressures. A still further advantage ofthe present method over the rolling method, which is most commonlypracticed, is that it avoids the danger of, either cutting through ormaterially reducing the thickness of the tube wall at the crests of thecorrugations, which has been a common cause of failure with bellowsmanufactured by mechanical or rolling methods. I

Other forms may be employed embodying the features of my inventioninstead of the one here explained, change being made in the form orconstruction, provided the elements stated by any of the followingclaims or the equivalent of such stated elements be employed, whetherproduced by my preferred method or by others embodying steps equivalentto those'stated in the following claims.

I therefore particularly point out and distinctly claim as myinvention 1. Ina method of making metallic bellows, the steps whichconsist in forming spaced inwardly extending shallow grooves in acylindrical metal wall. and then expanding such wall outwardly betweensuch grooves by the application of pressure uniformly against thesurface of said wall while supporting the outersurfaces of such groovesagainst expansion.

2. In a method of making metallic bellows, the steps which consist informing spaced inwardly extending shallow grooves in a cylindrical metalwall, and then applying an internal fluid pressure against such wallwhile supporting the outer surfaces of such grooves against expansion.

3. In a method of making metallic bellows, the steps which consist informing spaced inwardly extending corrugations in a cylindrical metalwall, and then applying an internal expansion fluid pressure againstsuch wall while supporting the outer surfaces of said inwardly extendingcorrugations against expansion during the expansion of the wall portionsbetween said firstnamed corrugations.

4. In a method of making metallic bellows, the steps which consist inforcing spaced'portions of a tubular metal wall inward to an amount*inducing the maximum safe working temper in the crest of thecorrugation thus formed, and then expanding the tubular wall betweensaid first-named inner corrugations by the application of fluid gpressure to form outwardly extending corrugations. between saidfirst-named inner .g

corrugations.

5; In a method of making metallic bellows,

the steps which consist in forcing space portions of a tubular metalwall inward to form inwardly extending corrugations therein, and thenexpanding the wall outwardly between such internally extendingcorrugations by the application of fluid pressure within such tubularwall to an amount inducing the maximum safe working temper in the crestsof the outer c'orrugationsthus formed, v

6. In' amethod of making metallic bellows, 'the steps which consist inforcing spaced portions of a tubular metal wall inward to an amountinducing the maximum safe working temper in the crest-of the corrugationthus formed, and .then expanding the wall outwardly between suchinwardly extending corrugations by the application of fiuicl pressure toan amount inducing the maximum safe working temper in the crests of theouter corrugations thus formed.

7. In the method of making metallic bellows, the ste s which consist informing spaced inwar ly extending shallow corrugations in acylindrical'metal wall, and then expanding such wall outwardly betweensuch corrugations by the application of pressure against the surface ofsaid wall.

8.- In a method of making metallic bellows, the steps which conslst inforcing spaced portions of a tubular metal wall in ward to form inwardlyextending corrugations therein, and then expanding the tubular wallbetween Said first-named inner corrugations to form outwardly extendingcorrugations between said first-named inner corrugations.

9. The process of making bellows consisting in providin a'tube of thinmetal, forming aseries 0 inwardly pressed spacediii li l;

apart annular grooves in and around said tube with connecting sectionsof said tube between said grooves, and then acting upon said groovedtube to form it into a flexible longitudinally expansible andcontractible bellows.

10. The process sisting in providing a plain elongated tube havin a thinwall, rolling a series of space -apart inwardly extending annulargrooves with unworked and unchanged connecting sections of said tubebetween the grooves havin the diameter of said tube, and then wor insaid connecting sections to form outwardI from said connecting sections.

11. The process of making bellowsconsisting in providing a lainelongated "tube havin a thin wall, orming a series of spaced-apartinwardly extendin annular ooves therein with uncorrugate connectsectionsof said wall between the ves, and then subjectingl sald connectmgsections to operations 12. The process of making bellows consistinginproviding a tube of thin metal, forming a series of inwardly pressedspaced-apart annular grooves in and around extending corrugations ofmaking bellows conich form outwardly extending corrugations. from said 1connecting sections.

said tube with connecting sections having the diameter of the tubebetween said inwardly pressed grooves, and then forming said connectingsections into outwardly extending corrugations.

13. The process of making bellows consisting in providing a thin walledmetal tube, rolling the metal of the tube inward to form grooves withconnecting portions having the same diameter as the tube between saidgrooves, and forming said connecting portions into outwardly extendingcorrugations while enlarging the diameter of the same. I

14. The process of making bellows consisting in providing a thin walledmetal tube, rolling a consecutive series of spacedapart grooves inwardlyin said tube toward the axis of the tube with unworked connectingportions of the tube between said.

grooves which are connected by sections having substantially the samediameter as the original tube, and then working said connecting sectionsoutwardly to form outwardly extending corrugations.

Signed by me, this 25 day of October, 1924.

HORACE B. FAY.

DISCLAIMER 1, 644,-823.-Horace B. Fay, Shaker Heights, Ohio. Mm'rnon orMAKING Mn'ranmc BELLOWS. Patent dated October 11', 1927. Disclaimerfiled October 17, I 1935,-by the assignee, The Fulton Sylphon Company IHereb enters disclaimer to that part of the claims in said specificationwhich is inthe f0 owing words, to wit:

1. In a method of making metallic bellows, the steps which consistinforming spaced inwardly extending shallow grooves in acylindricalmetal wall, and then expanding such wall outwardly between such groovesby the application of pressure uniformly against the surface of saidwall whilesupporting the outer surfaces of such grooves againstexpansion. v 1 2. In amethod of makinglmetallic bellows, the steps whichconsist in forming spaced inwardly extending sha owgropves in acylindrical metal wall, and then applying aninternal fluid pressureagainst such wall while supporting the outer surfaces of such groovesagainst expansion.

3. In a method of making metallic bellows, the-steps which consist informing I spaced inwardly. extending corrugations ina cylindrical metalwall, and then'applying an internal expansion fluid pressure againstsuch [wall while supporting the outer surfaces of said inwardlyextending corrugations aga nst expansion durmg'the expansion of the.wall portions between said first-named corrugations.

7. In the method of making metallic bellows, the steps which consist informing spaced inwardly extending shallow corrugations in a cylindricalmetal wall, and then expanding such wall outwardly between suchcorrugations by the application of pressure against the surface of saidwall. 1 In a methodof making metallic bellows, the steps which consistin forcing spaced portions of a tubular metal wall inward toforminwardly extending corrugations therein, and then expanding thetubular wall between said first-named inner corrugations to formoutwardly extending corrugations between said first-named innercorrugations. v 9. The process of making bellows consisting in providinga tubeof thin metal, forming a series of inwardly pressed spaced-apartannular grooves in-and around said tube with connecting sections of saidtube between said grooves, andthen acting upon iaild grooved tube toform it into a flexible longitudinallyexpansible and contractible eows.1

10. The process of making bellows consisting'in providing a plainelongated tube having a. thin wall, rolling a series of spaced-apartinwardly extending annular grooves with unworked and unchangedconnecting-sections of s'a'id tube between the grooves having thediameter of said tube, and then working said connecting sections to'form outwardly extending corrugations from said connecting sections.

11. The process of making bellowsconsisting' in'providing a plainelongated tube having a thin wall, forming a series of spaced-apartinwardly extending'annular groovestherein with uncorrugated connectingsections of said wall between the grooves, and then subjecting saidconnecting sections to operations which form outwardly extendingcorrugations from said conne'c ting sections.

12. The process of making bellows consisting in providing a tube of thinmetal,

forming a series of inwardly pressed spaced-apart annular groovesin andaround. said tube with-connecting sections having the diameter of the.tube between said inwardly pressed grooves; and then forming saldconnecting sections into outwardly extending corrugations.

13. The process of making-bellows nonsisting in providing athin walledmetal tube, rolling the metal of the tube inward to form grooves withconnecting portions having the samediameter as the tube between saidgrooves, and forming said connecting portions outwardlyextending'corrugations. hile enlarging-the diameter of the same.

" [Qfic'ialGazettc November 12, 1935.].

